This invention relates to a method and an installation for needling a fibre fleece using at least two needle bars placed successively on the path of the fleece, wherein the first of the needle bars may be more particularly but not limitatively intended to carry out a pre-needling step.
More specifically, the invention relates to a needling system in which the needle bars are operated with an “elliptical”-type movement, i.e. having a reciprocating penetration movement component, typically vertical, and a reciprocating progressive movement component, typically horizontal.
The progression component is synchronized with the penetration component in such a way that the needles in penetration position in the fleece accompany the progressive movement of the fleece through the needle loom. Thus, the needles can help to drive the fleece through the needle loom. Moreover, it is no longer necessary to stop the progression of the fleece when the needles are in their penetration phase.
On the other hand, the progression component constitutes an additional alternating movement affecting in particular the movable structure carrying the needle bar. Given the weight of this assembly, this results in vibrations parallel to the direction of progression, in particular at the high strike rates currently required by the users.
It is, admittedly, known to compensate for the effects of the vibrations by suitably orientated rotating counterweights, or by other means. But these compensation means are imperfect, heavy and expensive.